Bryant 551J installation instructions System, Controller, Smoke Detectors

Smoke Detectors —

Smoke detectors are available as factory-installed options on 551J models. Smoke detectors may be specified for Supply Air only or for Return Air without or with economizer or in combination of Supply Air and Return Air. Return Air smoke detectors are arranged for vertical return configurations only. All components necessary for operation are factory-provided and mounted. The unit is factory-configured for immediate smoke detector shutdown operation; additional wiring or modifications to unit terminal board may be necessary to complete the unit and smoke detector configuration to meet project requirements.

Units equipped with factory-optional Return Air smoke detectors require a relocation of the sensor module at unit installation. See “Completing Installation of Return Air Smoke Sensor:” on page 19 for details.

System

The smoke detector system consists of a four-wire controller and one or two sensors. Its primary function is to shut down the rooftop unit in order to prevent smoke from circulating throughout the building. It is not to be used as a life saving device.

Controller housing and electronics

Conduit couplings (supplied by installer)

Alarm

Duct smoke sensor controller

Conduit nuts (supplied by installer)

Conduit support plate

Terminal block cover

Cover gasket (ordering option)

Controller cover

Fastener (2X)

Trouble

Power

Test/reset

switch

551J

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Controller

The controller (see Fig. 29) includes a controller housing, a printed circuit board, and a clear plastic cover. The controller can be connected to one or two compatible duct smoke sensors. The clear plastic cover is secured to the housing with a single captive screw for easy access to the wiring terminals. The controller has three LEDs (for Power, Trouble and Alarm) and a manual test/reset button (on the cover face).

C08208

Fig. 29 - Controller Assembly

Duct smoke sensor

Sensor

The sensor (see Fig. 30) includes a plastic housing, a printed circuit board, a clear plastic cover, a sampling tube inlet and an exhaust tube. The sampling tube (when used) and exhaust tube are attached during installation. The sampling tube varies in length depending on the size of the rooftop unit. The clear plastic cover permits visual inspections without having to disassemble the sensor. The cover attaches to the sensor housing using four captive screws and forms an airtight chamber around the sensing electronics. Each sensor includes a harness with an RJ45 terminal for connecting to the controller. Each sensor has four LEDs (for Power, Trouble, Alarm and Dirty) and a manual test/reset button (on the left-side of the housing).

Air is introduced to the duct smoke detector sensor’s sensing chamber through a sampling tube that extends into the HVAC duct and is directed back into the ventilation system through a (shorter) exhaust tube. The difference in air pressure between the two tubes pulls the sampled air through the sensing chamber. When a sufficient amount of smoke is detected in the sensing chamber, the sensor

Exhaust tube

Exhaust gasket

See

Detail A

Intake gasket

TSD-CO2 (ordering option)

Plug

Sampling tube

(ordered separately)

Coupling

Detail A

Magnetic test/reset switch

Sensor housing and electronics

Cover gasket

(ordering option)

Sensor cover

signals an alarm state and the controller automatically takes the appropriate action to shut down fans and blowers, change over air handling systems, notify the fire alarm control panel, etc.

Alarm	Power
Trouble	Dirty

C08209

Fig. 30 - Smoke Detector Sensor

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